Herpesviridae & Poxviridae

Question 1

What group are Herpesviridae in?

Answer 1

Group 1–>dsDNA

Question 2

What polymerase do Herpes use?

Answer 2

-HOST DNA dep RNA pol
-VIRAL DNA dep DNA pol

Question 3

Are Herpes genome circular or linear

Answer 3

Linear
-biggest genome

Question 4

Are herpes enveloped/non and capsid shape

Answer 4

-Enveloped
-Icosahedral

Question 5

What 3 categories of herpes are there?

Answer 5

-Alpha (latent in neurons)
-Beta (latent in T cells)
-Gamma (cause cancer)

Question 6

What viruses are in alpha?

Answer 6

-Herpes simplex virus 1 & 2 (TORCH)
-Varicella zoster

Question 7

What viruses are in beta?

Answer 7

-Cytomegalovirus (TORCH)
-HHV6A, HHV6B, HHV7

Question 8

What viruses are in Gamma?

Answer 8

-Epstein Barr
-Kaposis sarcoma associated herpesvirus

Question 9

True or false: Herpesvirus does cross species transmission

Answer 9

False
-Herpesvirus does coevolution w/ humans–>good at staying hidden
-Less pathogenic

Question 10

True or false: Herpesvirus has a lytic infection

Answer 10

False
-Latent infection

Question 11

What is an episome?

Answer 11

Part of DNA that can replicate independently of host

Question 12

Why is latency a concern for Herpesvirus?

Answer 12

-Virus can reactivate at anytime
-Long term expression of viral products that can cause transfromation/cancer

Question 13

Where does latent virus reside in for long periods of time?

Answer 13

B lymphocytes and B memory cells
-these cells stay for life in body

Question 14

What is the tegument in Herpesviridae

Answer 14

Area in between capsid and envelope
-contains proteins (14) that immediately interact w/ host
-delivers proteins set up for cell viral replication & antagonize host

Question 15

Herpesviridae life cycle

Answer 15

1. Entry: Fusion/endocytosis
2. Nuclear entry & early proteins–>Immediate early & early (HOST DNA dep RNA pol)
3. Genome replication–>Late proteins (VIRAL DNA dep DNA pol) assembled in NUCLEUS
4. Exit: Exocytosis

Question 16

How many waves of transcription/protein production does Herpesviridae have?

Answer 16

3 waves
1. Immediate early (HOST DNA dep RNA pol)
2. Early (HOST DNA dep RNA pol)
3. Late (VIRAL DNA dep DNA pol)

Question 17

Herpesvirdae is linear how does it prevent degradation of ends?

Answer 17

Terminal repeat at ends
-makes genome circular by rolling circle mechanism

Question 18

Poxviridae is part of which group?

Answer 18

Group 1–>dsDNA

Question 19

Where does Poxviridae replicate?

Answer 19

Cytoplasm

Question 20

What kind of polymerase do Poxviridae have?

Answer 20

-VIRAL DNA dep RNA pol
-VIRAL DNA dep DNA pol

Question 21

Are Poxviridae enveloped/non

Answer 21

Enveloped

Question 22

True or false: Poxviridae coevolve

Answer 22

False
-Jump host/cross species transmission

Question 23

What pathogens are in Poxviridae

Answer 23

-Smallpox
-Monkeypox
-Tanapox
-Molluscum
-Animal-pox virus

Question 24

What is important about smallpox?

Answer 24

-Killed millions
-Zoonotic transmission–>became human specific
-Led to first vaccines
-First human virus eradicated

Question 25

True or false: Monkeypox, Cowpox, Chickenpox, etc come from that animal

Answer 25

False -Name of virus is not reservoir, it is just where symptoms were seen -Reservoir is most likely mouse

Question 26

What was significant about the rabbits in Australia?

Answer 26

-Australia became over ran with rabbits -Tried to kill rabbits with Myxoma virus (99.8% mortality rate)-->non pathogenic to Brazilian rabbits -Not all rabbits died-->rabbits evolved resistance

Question 27

Poxviridae life cycle

Answer 27

1. Entry: fusion/endocytosis 2. Early transcription & translation --> early VIRAL DNA dep RNA pol 3. Genome replication-->intermediate proteins (VIRAL DNA dep DNA pol) 4. Late Proteins 5. Cell lysis

Question 28

How many waves of transcription/protein production are there for Poxvirdae

Answer 28

3 waves 1. Early 2. Intermediate 3. Late

Question 29

Poxviridae genome characteristics

Answer 29

-terminal repeats at ends -ends are covalently linked (unlike adeno) -stays linear (unlike herpes)

Question 30

What 2 poxviral proteins block host immunity and how do they work?

Answer 30

1. K3L--> binds to dsRNA indirectly blocks PKR and OASs 2. E3L-->directly antagonizes PKR

Question 31

How does PKR work?

Answer 31

-Protein kinase R (PKR) recognizes any dsRNA -Phosphorylates eIF2a -When eIF2a is phosphorylated prevents protein translation

Question 32

Asfarviridae

Answer 32

-Group 1-->dsDNA -Arbovirus (only dsDNA) -causes fever in pigs -enveloped -viral pol